\documentclass[a4paper,12pt]{report}

\usepackage[margin=2cm]{geometry}

\setlength{\parindent}{0pt}

\newcommand{\InjoeyVar}[1]
{\textit{#1}}

\begin{document}
\thispagestyle{empty}
\begin{center}
{\Huge Ishs Music}\\
ABN: 99 999 999 999\\
1 ABC St, Somewhere, Victoria 9999\\
0400 000 000
\end{center}

\vspace{1em}
%% InjoeyBeginParse
To:\\
\InjoeyVar{CustName},
\InjoeyVar{CustOrg}\\
\InjoeyVar{CustAddrStreet1}\\
\InjoeyVar{CustAddrSuburb},
\InjoeyVar{CustAddrState}
\InjoeyVar{CustAddrPostCode}

\vspace{1em}
Date: \InjoeyVar{InvDate}\\
\textbf{Invoice} No.: \InjoeyVar{InvNum}

\vspace{1.2em}
%% InjoeyItems

\vspace{1em}
No GST has been charged.
\end{document}
